Articulating apparatus of a waterjet system and related technology

ABSTRACT

A waterjet system in accordance with at least some embodiments includes a carriage, a motion assembly configured to move the carriage horizontally relative to a workpiece, and a cutting head carried by the carriage. The waterjet system can also include a kinematic chain through which the cutting head is operably connected to the carriage. The kinematic chain can include first, second, and third joints rotatably adjustable about different first, second, and third axes, respectively. The carriage and the first and second joints can be configured to move the cutting head along a path relative to the workpiece while the cutting head directs a jet toward the workpiece to form a product. The third joint can be configured to shift a kinematic singularity away from the path to reduce or eliminate delay and corresponding reduced cutting accuracy associated with approaching the kinematic singularity.

INCORPORATION BY REFERENCE

The present application is a divisional of U.S. patent application Ser.No. 16/275,122 filed Feb. 13, 2019, issued as ______, which claimspriority to U.S. Provisional Patent Application No. 62/630,135, filedFeb. 13, 2018, and titled ARTICULATING APPARATUS OF A WATERJET SYSTEMAND RELATED TECHNOLOGY. Additionally, U.S. patent application Ser. No.14/333,469, filed on Jul. 16, 2014, issued as U.S. Pat. No. 9,720,399 onAug. 1, 2017 and titled GENERATING OPTIMIZED TOOL PATHS AND MACHINECOMMANDS FOR BEAM CUTTING TOOLS is incorporated herein by reference inits entirety. To the extent the foregoing application or any othermaterial incorporated herein by reference conflicts with the presentdisclosure, the present disclosure controls.

BACKGROUND

Waterjet systems (e.g., abrasive-jet systems) are used in precisioncutting, shaping, carving, reaming, and other material-processingapplications. During operation, waterjet systems typically direct ahigh-velocity jet of fluid (e.g., water) toward a workpiece to rapidlyerode portions of the workpiece. Abrasive material can be added to thefluid to increase the rate of erosion. When compared to othermaterial-processing systems (e.g., grinding systems, plasma-cuttingsystems, etc.) waterjet systems can have significant advantages. Forexample, waterjet systems often produce relatively fine and clean cuts,typically without heat-affected zones around the cuts. Waterjet systemsalso tend to be highly versatile with respect to the material type ofthe workpiece. The range of materials that can be processed usingwaterjet systems includes very soft materials (e.g., rubber, foam,leather, and paper) as well as very hard materials (e.g., stone,ceramic, and hardened metal). Furthermore, in many cases, waterjetsystems are capable of executing demanding material-processingoperations while generating little or no dust, smoke, and/or otherpotentially toxic byproducts.

In a typical waterjet system, a pump pressurizes fluid to a highpressure (e.g., 40,000 psi to 100,000 psi or more). Some of thispressurized fluid is routed through a cutting head that includes anorifice element having an orifice. Passing through the orifice convertsstatic pressure of the fluid into kinetic energy, which causes the fluidto exit the cutting head as a jet at high velocity (e.g., up to 2,500feet-per-second or more) and impact a workpiece. The orifice element canbe a hard jewel (e.g., a synthetic sapphire, ruby, or diamond) held in asuitable mount (e.g., a metal plate). In many cases, a jig supports theworkpiece. The jig, the cutting head, or both can be movable undercomputer and/or robotic control such that complex processinginstructions can be executed automatically.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present technology can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale. Instead, emphasis is placed on clearlyillustrating the principles of the present technology. For ease ofreference, throughout this disclosure identical reference numbers may beused to identify identical or at least generally similar or analogouscomponents or features.

FIG. 1 is a partially schematic and partially cross-sectional profileview of a waterjet system in accordance with at least some embodimentsof the present technology.

FIG. 2 is a profile view of a cutting head and kinematic chain of thewaterjet system shown in FIG. 1 with a nozzle of the cutting head in avertical orientation.

FIG. 3 is a profile view of the cutting head and kinematic chain of thewaterjet system shown in FIG. 1 with the nozzle of the cutting head inan off-vertical orientation.

FIG. 4A is a profile view of a cutting head and kinematic chain of awaterjet system in accordance with at least some embodiments of thepresent technology with a nozzle of the cutting head in a verticalorientation.

FIG. 4B is an enlarged view of a portion of FIG. 4A.

FIG. 5A is a profile view of the cutting head and kinematic chain shownin FIG. 4A with the nozzle of the cutting head in an off-verticalorientation.

FIG. 5B is an enlarged view of a portion of FIG. 5A.

FIGS. 6 and 7 are flow charts illustrating methods for operating awaterjet system in accordance with at least some embodiments of thepresent technology.

DETAILED DESCRIPTION

Waterjet systems typically include a carriage connected to an x/y motionassembly that precisely positions the carriage in a horizontal plane.The carriage carries a cutting-head assembly including an elongatenozzle through which a waterjet travels axially toward a workpiece. Insome waterjet systems, the nozzle is fixedly connected to the carriagesuch that the carriage can move the nozzle horizontally relative to theworkpiece, but the nozzle cannot tilt relative to the workpiece. Thistype of system is well-suited for making through cuts and straight blindcuts in a stationary workpiece, which may be sufficient to form simplethree-dimensional products. Forming complex three-dimensional products,however, typically requires use of a cutting-head assembly that allowsthe nozzle to tilt relative to a workpiece. Some conventionalcutting-head assemblies that allow the nozzle to tilt relative to aworkpiece include a kinematic chain with a first joint and a secondjoint in series between the nozzle and the carriage. The first jointallows the nozzle to rotate within a limited range about an off-verticalaxis. The second joint allows the nozzle to rotate 360 degrees about avertical axis. Together, these joints allow the nozzle to move into anyorientation in a spherical sector defined by the range of motion of thefirst joint.

Conventional two-joint cutting-head assemblies tend to be well-suitedfor processing that calls for infrequent large (e.g., greater than30-degree) angular changes in the orientation of the nozzle. Theseconventional cutting-head assemblies, however, tend to be poorly suitedfor processing that calls for frequent small (e.g., less than 10-degree)angular changes in the orientation of the nozzle. When the vertical axisof the second joint of a conventional two-joint cutting-head assembly iscoincident with the nozzle axis (also the waterjet axis), operating thesecond joint has no effect on the orientation of the nozzle. This isknown as a kinematic singularity. Near this kinematic singularity, themath that conventional waterjet systems use to determine the respectivepositions of the first and second joints to cause a desired orientationof the nozzle automatically calls for large rotations of the secondjoint. These large rotations of the second joint tend to bedisproportionate to the magnitude of the desired angular change in theorientation of the nozzle. Often, the time required to execute theselarge rotations of the second joint necessitates a temporarily decreasein cutting speed (i.e., the speed at which the motion system moves thenozzle horizontally). After a large rotation of the second joint iscomplete, the cutting speed may return to a steady-state speed. This isproblematic because waterjet processing is time dependent. Unlike aconventional milling tool (e.g., a grinding head), a waterjet forms akerf in a workpiece by erosion that progresses laterally to differentextents depending on the speed at which the waterjet moves relative tothe workpiece. In general, slower cutting speeds correspond to widerkerfs and faster cutting speeds correspond to narrower kerfs. Whencutting speed changes to accommodate operation of the second joint of aconventional two-joint cutting-head assembly during operation of thecutting-head assembly near a kinematic singularity, the overall kerfwidth for a cutting project will be variable. This, in turn, reduces thedimensional accuracy of the product.

Compounding the kinematic-singularity problem is the fact that operatinga conventional two-joint cutting-head assembly near the vertical-axiskinematic singularity can be very useful. For example, slightly tiltingthe nozzle in the direction of travel can increase cutting efficiency.In addition (and usually more importantly) slightly tilting the nozzleaway from an adjacent product wall is often the best way to reduce oreliminate undesirable taper. In waterjet processing, taper refers to adifference between the kerf width at the top of a cut and the kerf widthat the bottom of the cut. A typical waterjet cut has a slight taper, themost common type being V-shaped taper. V-shaped taper occurs because awaterjet loses some of its cutting energy as it cuts deeper into aworkpiece. Slightly more material is removed at the top of the cut wherethe waterjet enters the workpiece, than at the bottom of the cut wherethe waterjet exits the workpiece. V-shaped taper is usually associatedwith fast cutting. In general, the greater the cutting speed, the morepronounced the taper. Slightly tilting the nozzle away from beingperfectly aligned with the desired orientation of an adjacent productwall shifts the taper to a scrap wall opposite to the product wall. Thisoffsetting technique is very effective for reducing or eliminating theeffect of taper on the dimensional uniformity of the product wall.

The optimum nozzle tilt for reducing taper usually varies over thecourse of a cutting project. For example, when cutting speed during acutting project is low (e.g., as the waterjet approaches a corner), theeffect of taper may be less pronounced. In contrast, when cutting speedis high (e.g., along a straight cut), the effect of taper may be morepronounced. Accordingly, it can be desirable to reduce nozzle tilt inthe former case to avoid overcompensating for the taper, and to increasethe nozzle tilt in the latter case to avoid undercompensating for thetaper. These changes in nozzle tilt can be called for in any directiondepending on the orientation of the product wall adjacent to thewaterjet. Cutting speed changes may occur frequently over the course ofa cutting project, particularly if the desired product wall has manycorners. Furthermore, the optimum nozzle tilt to reduce or eliminatetaper is usually less than 10 degrees from the cut surface. A cuttingprogram that includes nozzle tilt to reduce or eliminate taper,therefore, often includes frequent small angular changes in theorientation of the nozzle.

If not for speed-related and taper-related nozzle tilt, most waterjetprocessing would occur with the nozzle in a vertical orientation to formvertical product walls. Indeed, this is the orientation of the nozzle inmost (if not all) waterjet systems in which the nozzle is fixed relativeto the carriage. When speed-related and/or taper-related nozzle tiltis/are introduced into a typical cutting project, the specified nozzletilt tends to be within 10 degrees off vertical. As discussed above, ina conventional two-joint cutting-head assembly, the second joint rotatesabout a vertical axis that aligns with the nozzle axis at a kinematicsingularity. Therefore, implementing speed-related and/or taper-relatednozzle tilt with a conventional two-joint cutting-head assembly wouldinvolve frequent small angular changes in the orientation of the nozzlenear the vertical-axis kinematic singularity. This would be impracticalbecause the cutting speed would need to decrease to allow time for thesecond joint to make frequent large rotations. The inventors recognizedthat one approach to addressing this problem is to allow the position ofthe second axis of a two-joint cutting-head assembly to be variable.This reduces kinematic-singularity-related delay in simple cuttingprojects calling for forming mostly vertical product walls. A problemwith this approach, however, is that kinematic-singularity-related delaymay still occur in more complex cutting projects calling for formingoff-vertical product walls. The inventors further recognized that addinga third joint to the kinematic chain between the nozzle and the carriagewould allow kinematic-singularity-related delay to be reducedsignificantly even in complex cutting projects.

Systems, devices, and methods in accordance with embodiments of thepresent technology can at least partially address one or more of theproblems described above and/or other problems associated withconventional technologies whether or not stated herein. For example,waterjet systems in accordance with at least some embodiments of thepresent technology have features that facilitate reliably avoidingkinematic-singularity-related delay. Specific details of systems,devices, and methods in accordance with various embodiments of thepresent technology are disclosed herein with reference to FIGS. 1-7 .Although the systems, devices, and methods may be disclosed hereinprimarily or entirely with respect to waterjet applications, otherapplications in addition to those disclosed herein are within the scopeof the present technology. For example, suitable features of describedwaterjet systems can be implemented in the context of plasma-cuttingsystems or other types of beam-cutting systems. Furthermore, it shouldbe understood, in general, that other systems, devices, and methods inaddition to those disclosed herein are within the scope of the presenttechnology. For example, systems, devices, and methods in accordancewith embodiments of the present technology can have different and/oradditional configurations, components, and procedures than thosedisclosed herein. Moreover, a person of ordinary skill in the art willunderstand that systems, devices, and methods in accordance withembodiments of the present technology can be without one or more of theconfigurations, components, and/or procedures disclosed herein withoutdeviating from the present technology.

Waterjet systems in accordance with at least some embodiments of thepresent technology can be used with a variety of suitable fluids, suchas water, aqueous solutions, hydrocarbons, glycols, and nitrogen. Assuch, although the term “waterjet” is used herein for ease of reference,unless the context clearly indicates otherwise, the term refers to a jetformed by any suitable fluid, and is not limited exclusively to water oraqueous solutions. The term “fluid,” as used herein, encompasses anysuitable fluid phase depending on the context. Furthermore, the term“fluid,” as used herein, may be substituted in suitable instances withany of the narrower terms “aqueous fluid,” “water,” “liquid,” “aqueousliquid,” and “liquid water” to indicate common examples of suitablefluids in the context of waterjet processing. References herein to“ultrahigh pressures” refer to pressures suitable for high-volumewaterjet processing of relatively hard materials. For example, the“ultrahigh pressures” described herein can be pressures greater than30,000 psi, such as pressures within a range from 30,000 psi to 120,000psi. It should be understood, however, that at least some features ofthe present technology can also be useful in the context of waterjetprocessing at lower pressures, such as pressures from 5,000 psi to30,000 psi. Finally, unless the context clearly indicates otherwise, theterms “cutting,” “cut,” and the like refer to any suitable materialmodification caused by a waterjet, such as through cutting, piercing,shaping, carving, reaming, etching, milling, eroding, etc.

FIG. 1 is a partially schematic and partially cross-sectional profileview of a waterjet system 100 in accordance with at least someembodiments of the present technology. As shown in FIG. 1 , the waterjetsystem 100 can include a carriage 102 carrying a cutting head 104 via akinematic chain 106. The cutting head 104 can be configured to direct awaterjet 108 toward a workpiece 110. The kinematic chain 106 can beconfigured to raise, lower, and tilt the cutting head 104 relative tothe workpiece 110 while the cutting head 104 directs the waterjet 108toward the workpiece 110. The waterjet system 100 can further include amotion assembly 112 configured to move the carriage 102 horizontallyrelative to the workpiece 110 while the cutting head 104 directs thewaterjet 108 toward the workpiece 110. Below the carriage 102, thewaterjet system 100 can include a catcher 114 containing a liquidreservoir 116 that dissipates the energy of the waterjet 108 after thewaterjet 108 passes through the workpiece 110. The waterjet system 100can also include slats 118 within the catcher 114 that support theworkpiece 110. Ultrahigh pressure fluid lines, abrasive lines, andpneumatic lines associated with forming the waterjet 108 and operatingthe cutting head 104 are not shown in FIG. 1 to enhance clarity.

The motion assembly 112 can include an x-axis subassembly 120 extendingbetween two mounting towers 122 extending upwardly from the catcher 114.The motion assembly 112 can also include a y-axis subassembly 124perpendicular to the x-axis subassembly 120. The x-axis subassembly 120can include an x-axis actuator 126 within an x-axis bellow seal 128.Similarly, the y-axis subassembly 124 can include a y-axis actuator 130within a y-axis bellow seal 132. The x-axis subassembly 120 and they-axis subassembly 124 can also include internal tracks, joints,actuators, etc., which are not shown in FIG. 1 to enhance clarity. Thecutting head 104 can be connected to the x-axis subassembly 120 via they-axis subassembly 124 such that the x-axis subassembly 120 moves boththe cutting head 104 and the y-axis subassembly 124. Together, thex-axis subassembly 120 and the y-axis subassembly 124 can move thecutting head 104 to any desired horizontal position within a rectangularfield. In FIG. 1 , the y-axis subassembly 124 is shown cantilevered offthe x-axis subassembly 120. Alternatively, a counterpart of the y-axissubassembly 124 can be part of a bridge extending between twocounterparts of the x-axis subassembly 120.

With continued reference to FIG. 1 , the waterjet system 100 can furtherinclude a user interface 134 and a controller 136. The user interface134 can be configured to receive input from a user of the waterjetsystem 100 and to send data based on the input to the controller 136.The input can include, for example, one or more specifications (e.g.,coordinates, geometries, dimensions, etc.) of a cutting project. Thecontroller 136 can include a processor 138 and memory 140 and can beprogrammed with instructions (e.g., non-transitory instructionscontained on a computer-readable medium) that, when executed, controloperation of the waterjet system 100. The controller 136 can be operablyconnected to the user interface 134, to the motion assembly 112, and tothe kinematic chain 106 via communication links 107. The communicationlinks 107 can be separate or combined, and can have any suitable form.For example, the communication links 107 can include any suitable wiredand/or wireless communication components, such as wires and transceivers(e.g., antennas, Wi-Fi access points, Bluetooth transceivers, nearfieldcommunication devices, wireless modems, etc.). In some cases, thecontroller 136 is local. In other cases, the controller 136 is remote.Furthermore, communication between the controller 136 and othercomponents of the waterjet system 100 can be direct or indirect (e.g.,via the Internet and/or via an intermediate computing system).

FIGS. 1 and 2 are profile views of the cutting head 104 and thekinematic chain 106 of the waterjet system 100. With reference to FIGS.1-3 together, the cutting head 104 can include an elongate nozzle 142and a waterjet outlet 144 at a distal end of the nozzle 142. Thekinematic chain 106 can include a first joint 146, a second joint 148,and a third joint 150 rotatable about different respective axes. Thefirst joint 146 can be in series between the cutting head 104 and thesecond joint 148. The second joint 148 can be in series between thefirst joint 146 and the third joint 150. The third joint 150 can be inseries between the second joint 148 and the carriage 102. In at leastsome cases, the kinematic chain 106 also includes a fourth joint 152 inseries between the third joint 150 and the carriage 102. The fourthjoint 152 can be linearly adjustable to move the cutting head 104vertically relative to the carriage 102.

The first joint 146, the second joint 148, and the third joint 150 canbe rotatably adjustable about a first axis 154 (illustrated as a line),a second axis 156 (also illustrated as a line), and a third axis 158(illustrated as an “x”), respectively, within a first range of motion, asecond range of motion, and a third range of motion, respectively. Thesecond range of motion can be greater than the first range of motion.Furthermore, the third range of motion can be less than the first rangeof motion and less than the second range of motion. For example, thethird range of motion can be less than or equal to 30 degrees (e.g.,less than or equal to 60 degrees and/or less than or equal to 90degrees), the first range of motion can be greater than 30 degrees andless than 360 degrees (e.g., greater than 60 degrees and less than 360degrees), and the second range of motion can be greater than or equal to360 degrees (e.g., +/−180 degrees, +/−360 degrees, +/−720 degrees,etc.). Each of the first joint 146, the second joint 148, and the thirdjoint 150 can include a rotary actuator (not shown) configured toautomatically execute movement instructions from the controller 136. Thefourth joint 152 can include a linear actuator (also not shown)configured to automatically execute movement instructions from thecontroller 136.

Rotatably adjusting the second joint 148 about the second axis 156 canchange the position of the first axis 154. Similarly, rotatablyadjusting the third joint 150 about the third axis 158 can change therespective positions of the first and second axes 154, 156. Rotatablyadjusting the third joint 150 about the third axis 158 can also move thethird joint 150 between a first state shown in FIG. 2 and a second stateshown in FIG. 3 . The second axis 156 can be vertical when the thirdjoint 150 is in the first state and not vertical when the third joint150 is in the second state. The second and third axes 156, 158 can havea fixed relationship, such as a fixed perpendicular relationship.Similarly, the first and second axes 154, 156 can have a fixedrelationship, such as a fixed coplanar relationship with a fixedintervening angle (e.g., 30 degrees). In at least some cases, the thirdaxis 158 is horizontal. Together, the first and second joints 146, 148can cause the nozzle 142 to have a specified orientation relative to theworkpiece 110 at a given time during a cutting project. Meanwhile, themotion assembly 112 and the fourth joint 152 can cause the nozzle 142 tohave specified horizontal and vertical positions, respectively, relativeto the workpiece 110. The nozzle 142 is shown coaxially aligned with thesecond axis 156 in FIGS. 2 and 3 to enhance clarity. During normaloperation of the waterjet system 100, the nozzle 142 may or may not bealigned with the second axis 156 at any given time.

Operating the third joint 150 is not necessary to achieve a full rangeof orientations of the nozzle 142. In other words, by operating only thefirst joint 146 and the second joint 148 the nozzle 142 can be orientedat any suitable angle relative to the workpiece 110 in a sphericalsector defined by the range of motion of the first joint 146. It isunderstandable, then, that conventional waterjet systems configured tomake angled cuts in workpieces do not include a counterpart of the thirdjoint 150. These conventional waterjet systems can be characterized astwo-axis systems. In contrast, the waterjet system 100 can becharacterized as a three-axis system. Adding the third joint 150 addscost and complexity to the waterjet system 100, but the inventors havediscovered that the previously unrecognized benefits of the third joint150 can outweigh this cost and complexity. Among these benefits is thepotential to use the third joint 150 to move a kinematic singularity asneeded to reduce or eliminate kinematic-singularity-related delay for acutting project. This is particularly useful for cutting projects thatcall for tilting the nozzle 142 to reduce or eliminate taper in aproduct wall. As discussed above, the appropriate nozzle tilts forreducing or eliminating taper in a product wall typically changefrequently within a small range in concert with changes in cuttingspeed. These conditions exacerbate kinematic-singularity-related delaywhen a kinematic singularity is within the small range. On the otherhand, shifting the kinematic singularity by just a small angle caneliminate or nearly eliminate this problem.

The third joint 150 can have one or more than one position during asingle cutting project. For example, when the third joint 150 has aposition that shifts a kinematic singularity so that the entire path thecutting head 104 is to follow to form a product does not cross orclosely approach the kinematic singularity, maintaining the third joint150 in that position throughout the cutting project may be appropriate.Alternatively, the third joint 150 may have different positions duringdifferent respective portions of a single cutting project when there isnot a position of the third joint 150 suitable for reducing oreliminating kinematic-singularity-related delay at all portions of thecutting project. In at least the former case, it can be advantageous forthe third joint 150 to be manually adjustable. In at least the lattercase, it can be advantageous for the third joint 150 to be automaticallyadjustable. In FIGS. 1 and 2 , the third joint 150 is shown as anautomatically (not manually) adjustable joint. As discussed below withreference to FIGS. 4A-4B, in other cases, a counterpart of the thirdjoint 150 can be manually adjustable. In these and still other cases,counterparts of the first and second joints 146, 148 can beautomatically adjustable.

FIGS. 4A and 5A are profile views of the cutting head 200 and akinematic chain 202 of a waterjet system in accordance with at leastsome embodiments of the present technology. FIGS. 4B and 5B are enlargedviews of portions of FIGS. 4A and 5A, respectively. With reference toFIGS. 4A-5B together, the kinematic chain 202 can include a third joint204 that is manually adjustable to any one of three states. For example,the third joint 204 can include partially overlapping plates 206 withholes 208 that align from one plate 206 to the other plate 206 when thethird joint 204 is in a given one of the three states. The third joint204 can also include a pin 210 shaped to be inserted through an alignedpair of the holes 208 to hold the third joint 204 in a corresponding oneof the states. In the illustrated case, the three states are azero-degree angle, a four-degree angle, and an eight-degree angle. InFIGS. 4A and 4B, the pin 210 is inserted into the holes 208corresponding to the zero-degree angle. In FIGS. 5A and 5B, the pin 210is inserted into the holes 208 corresponding to the eight-degree angle.Whether manually adjustable or automatically adjustable, the third joint204 and its counterparts can be step joints with a relatively smallnumber of steps (e.g., at most 10 steps) rather than infinitely variablejoints. This can be useful, for example, to reduce the complexity of themath used to control operation of the overall kinematic chain 202. Inother cases, counterparts of the third joint 204 can be manually orautomatically adjustable continuously rather than stepwise.

FIGS. 6 and 7 are flow charts illustrating methods 300, 400,respectively, for operating a waterjet system in accordance with atleast some embodiments of the present technology. The methods 300, 400will be described with reference to features of the waterjet system 100shown in FIGS. 1-3 . It should be understood, however, that the methods300, 400 and counterparts thereof are not limited to these features. Asshown in FIG. 6 , the method 300 can include operating the third joint150 to rotate the cutting head 104, the first joint 146, and the secondjoint 148 about the third axis 158 relative to the workpiece 110 (block302). For example, this can include moving the third joint 150 from afirst state in which the second axis 156 is vertical to a second statein which the second axis 156 is not vertical. Alternatively or inaddition, operating the third joint 150 can include moving the thirdjoint 150 between two or more states in which the second axis 156 is offvertical by different respective angles. The movement of the third joint150 can be stepwise or continuous, and can be automatic or manual. Next,the method 300 can include directing the waterjet 108 toward theworkpiece 110 via the cutting head 104 (block 304). In some cases,moving the third joint 150 occurs only before directing the waterjet 108toward the workpiece 110. In other cases, moving the third joint 150occurs while directing the waterjet 108 toward the workpiece 110.

The method 300 can further include moving (e.g., at varying speed) thecarriage 102 horizontally relative to the workpiece 110 (block 306),operating the first joint 146 to rotate the cutting head 104 about thefirst axis 154 relative to the workpiece 110 (block 308), operating thesecond joint 148 to rotate the cutting head 104 and the first joint 146about the second axis 156 relative to the workpiece 110 (block 310), andoperating the fourth joint 152 to move the cutting head 104, the firstjoint 146, the second joint 148, and the third joint 150 verticallyrelative to the workpiece 110 (block 312). These operations can occurautomatically in concert while directing the waterjet 108 toward theworkpiece 110. Together, these operations can move the cutting head 104along a path configured to form a product from the workpiece 110. Thewaterjet 108 can have different angles off vertical at differentrespective portions of the path. In at least some cases, the pathincludes adjustments in an angle by which the waterjet 108 is tiltedrelative to an adjacent wall of the product, thereby reducing oreliminating taper in the wall of the product, the taper being thatassociated with a non-cylindrical shape of the waterjet 108. When thespeed at which the carriage 102 moves horizontally relative to theworkpiece 110 varies, the adjustments in the angle by which the waterjet108 is tilted relative to the adjacent wall of the product can at leastpartially compensate for an effect of the varying speed on the taper.Moving the third joint 150, which (as mentioned above) can occur beforeand/or while moving the cutting head 104 along the path, can shift akinematic singularity away from the path.

As shown in FIG. 7 , the method 400 can include receiving a geometry ofa product to be cut from the workpiece 110 (block 402). For example, thegeometry can be vector model of the product. The method 400 can furtherinclude generating instructions for moving the cutting head 104 along apath relative to the workpiece 110 while the cutting head 104 directsthe waterjet 108 toward the workpiece 110 to form the product. This caninclude generating instructions for operating the motion assembly 112(block 404), generating instructions for operating the first joint 146(block 406), generating instructions for operating the second joint 148(block 408), and generating instructions for operating the third joint150 (block 410). The instructions for operating the motion assembly 112can include instructions for operating the motion assembly 112 to movethe cutting head 104 horizontally at different respective speeds atdifferent respective portions of the path. Correspondingly, theinstructions for operating the first and second joints 146, 148 caninclude instructions for operating the first and second joints 146, 148to at least partially compensate for an effect of the differenthorizontal speeds on taper in a wall of the product, the taper beingthat associated with a non-cylindrical shape of the waterjet 108. Inthese and other cases, the instructions for operating the first andsecond joints 146, 148 can include instructions for operating the firstand second joints 146, 148 to reduce or eliminate the taper. Theinstructions for operating the third joint 150 can include instructionsfor operating the third joint 150 to shift a kinematic singularity awayfrom the path.

The method 400 can further include prompting a user of the waterjetsystem 100 to manually operate the third joint 150 to shift a kinematicsingularity away from the path. For example, the controller 136 cancalculate a suitable position for the third joint 150 to avoid kinematicsingularities based on the complete instructions for a given cuttingoperation. A corresponding algorithm can include determining the anglebetween the nozzle axis and the second axis 156 at each increment duringthe cutting operation, calculating a minimum angle of the third joint150 to prevent the angle between the nozzle axis and the second axis 156from being zero at any increment, and then adding a buffer (e.g., 10degrees) to the calculated minimum angle. The controller 136 can thendetermine a setting (e.g., a stepwise setting) for the suitable positionof the third joint 150. The waterjet system 100 can then communicatethis setting to a user of the waterjet system 100 via the user interface134. After the user manually operates the third joint 150 in response tothe communication, the method 400 can include automatically operatingthe first joint 146, the second joint 148, and the motion assembly 112based at least partially on the instructions. Alternatively, thecontroller 136 can automatically operate the first joint 146, the secondjoint 148, the third joint 150, and the motion assembly 112 based atleast partially on the instructions.

The third joint 150 can have the same or different positions during thefull duration of a cutting operation. Causing the third joint 150 tohave different positions during the full duration of a cutting operationcan be useful, for example, when the cutting operation involves formingwalls at significantly different respective angles off vertical andcompensating for taper. In these and other cases, no single position ofthe third joint 150 may be adequate to avoid kinematic singularitiesthroughout the full duration of the cutting operation. Accordingly, thecontroller 136 can determine different suitable positions for the thirdjoint 150 at different respective portions of the cutting operation. Acorresponding algorithm can be the same as the algorithm described abovefor determining a single suitable position for the third joint 150,except performed on different subsets of all increments within thecutting operation. When the subsets are very small, control of the thirdjoint 150 can be dynamic and in concert with operation of the firstjoint 146 and the second joint 148. Other control methods involving thethird joint 148 are also possible.

This disclosure is not intended to be exhaustive or to limit the presenttechnology to the precise forms disclosed herein. Although specificembodiments are disclosed herein for illustrative purposes, variousequivalent modifications are possible without deviating from the presenttechnology, as those of ordinary skill in the relevant art willrecognize. Accordingly, this disclosure and associated technology canencompass other embodiments not expressly shown or described herein. Insome cases, well-known structures and functions have not been shown ordescribed in detail to avoid unnecessarily obscuring the description ofembodiments of the present technology. Although steps of methods may bepresented herein in a particular order, in alternative embodiments, thesteps may have another suitable order. Similarly, certain aspects of thepresent technology disclosed in the context of particular embodimentscan be combined or eliminated in other embodiments. Furthermore, whileadvantages associated with certain embodiments may have been disclosedin the context of those embodiments, other embodiments can also exhibitsuch advantages, and not all embodiments need necessarily exhibit suchadvantages or other advantages disclosed herein to fall within the scopeof the present technology.

Certain aspects of the present technology may take the form ofcomputer-executable instructions, including routines executed by acontroller or other data processor. In some embodiments, a controller orother data processor is specifically programmed, configured, orconstructed to perform one or more of these computer-executableinstructions. Furthermore, some aspects of the present technology maytake the form of data (e.g., non-transitory data) stored or distributedon computer-readable media, including magnetic or optically readable orremovable computer discs as well as media distributed electronicallyover networks. Accordingly, data structures and transmissions of dataparticular to aspects of the present technology are encompassed withinthe scope of the present technology. The present technology alsoencompasses methods of both programming computer-readable media toperform particular steps and executing the steps.

Throughout this disclosure, the singular terms “a,” “an,” and “the”include plural referents unless the context clearly indicates otherwise.Similarly, unless the word “or” is expressly limited to mean only asingle item exclusive from the other items in reference to a list of twoor more items, then the use of “or” in such a list is to be interpretedas including (a) any single item in the list, (b) all of the items inthe list, or (c) any combination of the items in the list. Additionally,the terms “comprising” and the like are used throughout this disclosureto mean including at least the recited feature(s) such that any greaternumber of the same feature(s) and/or one or more additional types offeatures are not precluded. Directional terms, such as “upper,” “lower,”“front,” “back,” “vertical,” and “horizontal,” may be used herein toexpress and clarify the relationship between various elements. It shouldbe understood that such terms do not denote absolute orientation.Reference herein to “one embodiment,” “an embodiment,” or similarformulations means that a particular feature, structure, operation, orcharacteristic described in connection with the embodiment can beincluded in at least one embodiment of the present technology. Thus, theappearances of such phrases or formulations herein are not necessarilyall referring to the same embodiment. Furthermore, various particularfeatures, structures, operations, or characteristics may be combined inany suitable manner in one or more embodiments.

I/We claim:
 1. A method for operating a waterjet system, the methodcomprising: directing a jet toward a workpiece via a cutting head of thewaterjet system; moving a carriage of the waterjet system horizontallyrelative to the workpiece while directing the jet toward the workpiece,wherein the cutting head is operably connected to the carriage through akinematic chain of the waterjet system; operating a first joint of thekinematic chain to rotate the cutting head about a first axis relativeto the workpiece while directing the jet toward the workpiece; operatinga second joint of the kinematic chain to rotate the cutting head and thefirst joint about a second axis relative to the workpiece whiledirecting the jet toward the workpiece; operating a third joint of thekinematic chain to rotate the cutting head, the first joint, and thesecond joint about a third axis relative to the workpiece; and operatinga fourth joint of the kinematic chain to move the cutting head, thefirst joint, the second joint, and the third joint vertically relativeto the workpiece.
 2. The method of claim 1 wherein operating the thirdjoint includes operating the third joint before directing the jet towardthe workpiece.
 3. The method of claim 1 wherein operating the thirdjoint includes operating the third joint while directing the jet towardthe workpiece.
 4. The method of claim 1 wherein operating the thirdjoint includes moving the third joint from a first state in which thesecond axis is vertical to a second state in which the second axis isnot vertical.
 5. The method of claim 1 wherein operating the third jointincludes operating the third joint stepwise.
 6. The method of claim 1wherein: operating the first and second joints includes automaticallyoperating the first and second joints; and operating the third jointincludes manually operating the third joint.
 7. The method of claim 1wherein operating the first, second, and third joints includesautomatically operating the first, second, and third joints.
 8. Themethod of claim 1 wherein: moving the carriage, the first joint, and thesecond joint includes moving the carriage, the first joint, and thesecond joint to move the cutting head along a path configured to form aproduct from the workpiece; and the jet has different angles offvertical at different respective portions of the path.
 9. The method ofclaim 8 wherein: operating the third joint includes moving the thirdjoint to a state selected to shift a kinematic singularity away from thepath; and moving the carriage, the first joint, and the second jointincludes moving the carriage, the first joint, and the second joint tomove the cutting head along a full extent of the path while the thirdjoint is in the selected state.
 10. The method of claim 8 whereinoperating the third joint includes operating the third joint to shift akinematic singularity away from the path.
 11. The method of claim 8wherein operating the first and second joints includes operating thefirst and second joints to adjust an angle by which the jet is tiltedrelative to an adjacent wall of the product thereby reducing oreliminating taper in the wall of the product, the taper being associatedwith a non-cylindrical shape of the jet.
 12. The method of claim 11wherein: moving the carriage horizontally relative to the workpieceincludes moving the carriage horizontally relative to the workpiece atvarying speed; and adjusting the angle by which the jet is tiltedrelative to the adjacent wall of the product includes adjusting theangle by which the jet is tilted relative to the adjacent wall of theproduct to at least partially compensate for an effect of the varyingspeed on the taper.